Table of Contents
Can a single processes be deadlock?
It is not possible to have a deadlock involving only one single process. The deadlock involves a circular “hold-and-wait” condition between two or more processes, so “one” process cannot hold a resource, yet be waiting for another resource that it is holding.
How deadlock can be detected explain?
A deadlock exists in the system if and only if there is a cycle in the wait-for graph. In order to detect the deadlock, the system needs to maintain the wait-for graph and periodically system invokes an algorithm that searches for the cycle in the wait-for graph.
What are 4 conditions required for deadlock to occur?
Conditions for Deadlock- Mutual Exclusion, Hold and Wait, No preemption, Circular wait. These 4 conditions must hold simultaneously for the occurrence of deadlock.
Can single thread do deadlock?
Yes, a single-threaded application can deadlock if you have locks that are not re-entrant and a thread attempts to reacquire a lock that it owns already (like via a recursive call).
What is deadlock explain with example?
A deadlock is a condition where a program cannot access a resource it needs to continue. For example, the following situation will cause a deadlock between two processes: Process 1 requests resource B from process 2. Resource B is locked while process 2 is running.
What is deadlock explain?
In an operating system, a deadlock occurs when a process or thread enters a waiting state because a requested system resource is held by another waiting process, which in turn is waiting for another resource held by another waiting process.
What is the approach of an operating system to detect a deadlock for single instance of resource type and multiple instance of resource type explain with example?
If all resources have only a single instance, then we can define a deadlock-detection algorithm that uses a variant of the resource-allocation graph, called a wait-for graph.
What are the necessary and sufficient conditions for deadlock explain with the help of examples?
Mutual Exclusion this condition is needed to be checked for non-sharable resources (e.g. Printer) No preemption If a process that is holding some resources requests another resource that cannot be immediately allocated to it, then all resources currently being held are released.
Can a single process be deadlocked 1 marks?
These definitions imply that for a deadlock to occur there must be AT LEAST two processes. So, the case where a single process tries to re-acquire the same resource is NOT a deadlock.
Can a deadlock happen with three threads?
Thread Deadlock Deadlock can occur when multiple threads need the same locks, at the same time, but obtain them in different order.
How deadlocks can be prevented explain with example?
order of numbering. For Example, if P1 process is allocated R5 resources, now next time if P1 ask for R4, R3 lesser than R5 such request will not be granted, only request for resources more than R5 will be granted. Deadlock avoidance can be done with Banker’s Algorithm.
How can deadlock be overcome?
Deadlocks can be prevented by preventing at least one of the four required conditions:
- 7.4.1 Mutual Exclusion. Shared resources such as read-only files do not lead to deadlocks.
- 2 Hold and Wait.
- 3 No Preemption.
- 4 Circular Wait.